Process for removing printers&#39; ink from printed paper by means of bleaching substances having an alkaline action.



UNITED} sTATEs PATENT O FIC Hneo HENKEL, or nussnnnonr, AND o'rroens'sicnn, or AUGSBURG, GERMANY.

PROCESS FOR REMOVING PRINTERS INK FROM PRINTED PAPER BLEACHINGSUBSTANCES HAVING AN ALKALINE. ACTION.

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Specification of Letters Patent.

Application filed December 2, 1909. Serial No. 531,085.

BY MEANS or Toall whom it may concern:

Be it known that We, HUoo 'HEN EL, Ph. D., chemist, and O'r'ro Gnssnnn,director, subjects of the King of Prussia and the 5 King of Bavaria,residing Dusseldorf,

Prussia, and Augsburg, Bavaria, Germany,

have invented certain new and useful improvementsin processes forremoving prin ters ink from printed paper by means of bleachingsubstances having an alkaline action, of which the following is aspecification.

It has been attempted for a long time to use printed paper again forpaper manufachitherto, owing to the printers ink adhering to the saidpaper, having such a great dyeing power that only infinitely small percentages of printed paper could be used for manufacturing new paper.Moreover, onl an inferior qualityaoi paper was produce It has also beenattempted to remove printersink from the paper but such attempts havenot given any satisfactory result. This is due chiefly to the fact thatprinters ink mainly consists of soot mixed with oil and settled sofirmly in the slim mass, when the printed paper'is treate that it isimpossibletowash it out..-

This invention relates to a process by means of whichit is possible tofree the printed paper from printers ink without the above mentioneddisadvantages. V

The process chiefly consists in the soaked and divided pa er beingtreated in an alkaline solution '0 peroxids in the"presence ofsubstances which during the process pass into a colloidal state. Asperoxids the rium superoxid BaO and the like. As col;

loidal substances, either silicic acid, already in colloidal state, canbe added or compounds can be used which, during the process, pass 1 intothe colloidal state, for instance silicates,

. alumina compounds and the like. The silicic acid develops ina colloidstate as the hydrosol' of the acid passes over'into the hydrogel. of theacid. Fine transparent flakes are then formed which may bacalled colloidsilicic acid. It is preferred to employ the so-called ture. The attemptshave, however, failed peroxids of alkalis or of earth alkalis may besoluble silicic acid which is on the market and consists of a compoundof water glass and soda, which upon being dissolved in water undergoes ahydrolytic decomposition of such nature that the silicic acid isprecipitated in colloidal form. This precipitation of the silicic acidcommences after a few minutes and is completed within four or fivehours. Of course,.th e rapidityof this preciptation depends upon theconcentration and the temperature. 'Newly precipitated aluminum hvdroxidAl(OH) +xI-I,O acts in "the same manner.

mIt has been found that the fat contained in-printers ink, is modifiedin the alkaline. solution of the superoxids 111 such "manner that itloses its binding or cementm'g iorce,

Patented Apr. 4,1911.

whereupon it becomes possible for the printers ink to be-converted.intoan emulsion by the colloidal silicic acid and thus easily separated fromthe fibers.

' The process is carried outdt'or instance,

in such manner that the old rinted paper is stirred in warm water,whereupon the above mentioned additions olf superoxids and colloidalsilicic acid, are made. After the reaction is completed, the paper massis separated from the liquid an'd'can be further purified by additionalwashing.

Compared to other bleaching substances suggested for the samepurposesuch. as.

Javelle water chlorid of lime and the like,

the peroxids used in the process just described, have the greatadvantage that the fibers are not so strongly attacked as by the othersubstances. The peroxids on the con: trary act throughout in a harmlessmanner, so that the material bleached isnot damaged. Altogether thebleaching action of the peroxids in the present process plays merely asecondary part. Of great importance is the actionof the vperoxldson theprinters ink of the paper, the oily bindin medium of which is resinifiedor saponifie and thus dissolved' The ink or soot nolonger adherin to thefiber, can be absorbed by, the colloi al silicic acid. This actionpfgelatin can be compared to the well known process of forming an emulsionwhen Washing with soap, in which it is assumed that the soap ishydrolytically split in the water into free alkali and aci -fattyacid-salt, the former dissolving the dirt'while the latter incloses andremoves the particles of dirt during the washing action.' A similardissolving, ab-

sorption and easy removal of printers ink has been impossible hitherto,so that the attempts to treat newspaper again were hithertounsuccessful.

By means of the process according to this invention the said removal ofprinters ink can be effected in a sim le, quick and cheap manner,without the fi rs being damaged or partly destroyed, as is the case whenchlorin compounds are used.

That what we claim and desire to secure by Letters Patent is:

l. A process for removing printers ink from printed paper pulp by meansof bleaching substances having an alkaline action, characterized by theprinted paper pulp being treated with peroxids in the presence ofsubstances which during the process pass into a colloidal state.

2. A process of removing printers ink from printed paper pulp by imeansof bleaching substances having an alkaline action, characterized by theprinted paper pulp being treated with an alkaline solution of a peroxidof alkali in the presence of substances which during the process passinto a colloidal state.

3. A process for removing printers ink from printed paper pulp by meansof bleaching substances having an alkaline action, characterized by therinted aper pulp being treated with an alkaline so utlon of a peroxid ofearth alkali in the presence of su stances which during the process passinto a. colloidal state.

4. A process for removing printers ink from printed paper pulp by meansof bleaching substances having an alkaline action, characterized by theprinted paper pulp being treated with peroxids and a substance beingalready in a colloidal state.

5. A process for removing printers ink from printed paper pulp by meansof bleaching substances having an alkaline action, characterized by theprinted aper pul being treated with peroxids and colloida l silicicacid.

In testimony whereof we have hereunto set our hands in presence of twosubscribing witnesses.

HUGO HENKEL. [Ls] OTTO GESSLER. Witnesses as to Hugo Henkel:

Orro Komc,

WILLY KLEIN. \Vitnesses as to Otto Gessler:

Lours MUELLER,

MATHILDE K. HELD.-

